Apparatus for exhausting air from packages made of tubular material



Dec. 10, 1963 H. THURLINGS APPARATUS FOR EXHAUSTING AIR FROM PACKAGESMADE OF TUBULAR MATERIAL Filed Dec. 27, 1961 rm 7 55 9 m1 INVENTOF"HERMA NN TH U R L MM 8 a g W United States Patent 3,113,409 APPARATUSFOR EXHAUSTHN G AIR FROM PACK- AGES MADE 9F TUiiULAR MATERIAL HermannThiirlings, Viersen, Bezirk Dusseldorf, Germany, assignor toHamac-Hansella Aktiengeselisehait,

a corporation of Germany Fiied Dec. 27, 1961, Ser. No. 162,474 Claimspriority, application Germany Get. 14, 1961 3 Claims. (Cl. 53112) Thisinvention relates generally to the art of packaging, and has particularreference to the production of packages composed of tubular material.The invention is directed to a method and apparatus for drawing offsurplus air from the packages immediately prior to the time they aresealed.

In the production of packages of this kind, the general procedureinvolves the formation, in the packaging machine, of a tube of packagingmaterial furnished in the form of a continuously-fed web.

The newly-formed tube is advanced step-wise in a longitudinal directionand transversely sealed by a pair of heated sealing jaws. A fillingdevice is so arranged with respect to the tube that the product to bepackaged is introduced into the successive bags as they are formed bythe transverse sealing operation. The sealing jaws operate so that eachtransverse seal closes off the bag that has just been filled and definesthe floor or lower seal of the next succeeding bag. After the jaws cometogether to produce the seal, they move downwardly so that a furtherlength of the just-formed tubes of packaging material is drawn intofilling position.

As a result of this procedure there is ordinarily sealed into each bag,in addition to the articles to be packed therein, a certain amount ofair. This is a conspicuous and definite disadvantage, since largequantities of these packages are generally packed together in largercontainers, such as cartons or the like, and as a result of the air ineach package a large amount of packing space is lost in the largercontainer. Moreover, the individual packages that happen to be at thebottom of such a large carton are not always strong enough to withstandthe continuous pressure upon them due to the weight of the packagesabove, as a result of which the locked-in air either gradually leaksout, so that the carton appears ultimately as though it had beeninsufficiently filled with packages, or the underlying packages mayactually burst, especially in the region of the seams.

Although these disadvantages have existed for many years, no simple wayhas been found, until now, of withdrawing the surplus air from packagesof the character described. Devices that have been suggested for thispurpose are either too complicated or operate unsatisfactorily.

It has now been found that in a startlingly simple manner, the surplusair can be drawn oif. This can be achieved by blowing air into the tubeof packaging material, just before the bag to be evacuated is sealed.The air blast is directed substantially opposite to the direction ofadvancement of the tube under the influence of the sealing jaws, i.e.,the air is blown into the tube in the general direction in which thesurplus air is to be withdrawn from the bag about to be sealed. Thisprocedure may be carried out in an unusually simple manner, since verysmall volumes of air accomplish the desired purpose when they areinjected in the form of pulses or bursts of air into the tube in thedirection specified. It has been found particularly advantageous tointroduce the air into the tube during the period when, in the normalcourse of closing the bag mouth, the cross-section of the tube at themouth has already become somewhat narrowed.

Patented Dec. 1%, i963 ice A preferred embodiment of the apparatus isillustrated in the accompanying drawings in which:

FIG. 1 is a schematic representation of the essential parts of apackaging machine of the character described prior to the operation ofthe transverse sealing jaws to seal off the filled bag;

FIG. 2 is a view similar to FIG. 1 showing the jaws during the sealingoperation;

FIG. 3 is an enlarged cross-sectional detail of the lower part of thefilling device of FIG. 2; and

FIG. 4 is a view similar to the lower part of FIG. 2 showing theconventional sealing operation whereby a volume of surplus air istrapped in the bag that has been sealed.

By means of a forming shoe or guide 1 of known character, a continuouslyadvancing web of packaging material 2 is formed into a tube 3 which isdrawn downwardly over the tubular filling pipe 4. The filling pipe 4 isprovided at the top with a hopper and feeding mechanism (not shown indetail) whereby predetermined charges are introduced into and throughthe filling tube, to the bag below it.

For the purpose of sealing the longitudinal seam of the tube 3, alongitudinal sealing iron or pressure pad 5 is provided. Transversesealing of the tube to form individual bags is effected by a pair oftransversely movable sealing jaws 6 which, in known fashion, move towardand away from each other. In addition, the jaws 6 are movable,longitudinally with respect to the tube. In practice, the jaws areseparated during the upward movement to the position shown in FIGS. 1and 2 at which point they move together to seal the bag. Then, whilethey remain together, they move downwardly and draw another length ofthe tube into position for the next filling operation. The pattern ofmovement of the jaws 6 is indicated by the arrows in FIG. 2.

The longitudinal sealing iron 5 is mounted on a piston 7, the head 8 ofwhich is movable in a cylinder 9. Seated against one side of the piston8 is a compression spring 16. On the other side of the piston thecylinder 9 is connected to an inlet conduit 11, leading from a three-waysolenoid valve 12. From this valve a conduit 13 extends into the fillingpipe 4 down to the bottom thereof. At that point, the conduit 13 is soformed (see FIG. 3) that it expels air in a direction generally oppositeto the direction in which the sealing jaws move the tube 3, as indicatedby the lines shown in FIG. 2. The valve 12 is also connected to an inletpressure source 14.

The apparatus operates as follows:

By control of the valve 12 and the movements of the transverse jaws 6 inpredetermined timed relation, pressure fluid from the inlet 14 isintroduced through conduit 11 to the piston 8, to advance and thusoperate the longitudinal sealing device 5, whenever the jaws 6 have beenseparated and are moving upwardly. The sealing iron 5 cooperates withthe filling pipe 4 to seal the overlapping longitudinal margins of thematerial 2 and thus maintain it in tubular form. Shortly before thetransverse jaws 6 contact each other to seal the just-filled bag, thevalve 12 is actuated to close the connection between the pressure inlet14 and the conduit 11. At the same time, the valve connects the conduit11 to the conduit 13. As a result, the spring 10 is allowed to move thepiston 8 leftwardly to the position shown in FIG. 2, whereby thelongitudinal sealing iron 5 disengages the section of the tube 3 it hasjust sealed. The pressurized air in the conduit 11, as well as the smallamount of air that was in the cylinder 9 before the piston 8 returned tothe position of FIG. 2, pulses through the conduit 13 and is ejectedfrom the outlet opening at the bottom thereof. This pulse or blast is ina direction opposite to that in which the packaging material travels.Consequently, the surplus air above the articles in the just-filled bagis sucked upward so that the walls of the bag come together snugly overthe articles within the bag, as shown in FIG. 2.

It has been found effective to introduce this pressure blast or pulseafter the sealing jaws 6 have already moved substantially toward eachother, whereby only a relatively narrow, rapidly closing, opening existsbetween the bag Walls and hence between the filled bag and the space inthe tube directly above the jaws 6.

During the closing movement of the jaws 6 toward each other, thelongitudinal sealing device 5 remains in the lifted position shown inFIG. 2. After they engage each other, the jaws 6 move downwardly to drawa new length of the tube 3 into filling position. As soon as thismovement of the jaws has been completed, the valve 12 is actuated inorder to reestablish the connection between the pressure fluid frominlet 14 and the conduit 11 so that the longitudinal sealing element 5is again moved forwardly to produce a longitudinal seam on a new lengthof the tube. The operation is then repeated.

The invention has been illustrated in a preferred form of packagingmachine, in which the movements of the longitudinal seaming device 5 arepneumatically controlled, and in which the exhausting of the pneumaticdevice is employed for the purpose of producing the pressure blast inthe filling pipe. The invention is, however, by no means restricted topneumatically operable packaging machines or mechanisms. In machineswhich operate by other than pneumatic means, the pressure tube 13 can beconnected to a small pump or the like which is operated in timedrelation to the operation of the packaging machine, instead of to thethree-way valve 12. In this way pressure blasts may be produced inpulses for the purpose of drawing off the surplus air from each bag asit is about to be sealed.

What is claimed is:

1. In a packaging machine having a filling pipe, a tube of packagingmaterial disposed around the pipe, and a pair of transversely movbalesealing jaws beneath the filling pipe, the lower end of the tube beingclosed and depending from the lower end of the pipe to a point below thesealing jaws and said jaws being movable toward each other to seal thetube at a point above its lower end, means for drawing off the surplusair from the lower end of the tube comprising a pneumatic system forcreating a discontinuous air blast, a conduit connected to saidpneumatic system and extending into said filling pipe, the lower end ofsaid conduit being so oriented that the air blast is introduced intosaid pipe in a direction away from the lower end of the tube, and acontrol valve associated with said pneumatic system for introducing saidair blast into said pipe immediately prior to the engagement of the jawsto seal the tube.

2. In a packaging machine, the apparatus defined in claim 1 including asealing iron operated by said pneumatic system for sealing thelongitudinal seam of the tube of packaging material.

3. In a packaging machine, the apparatus defined in claim 2 wherein saidpneumatic system comprises an inlet connection, a piston within acylinder connected to said sealing iron by a piston rod, a spring urgingsaid piston and hence said iron to an inoperative position, a secondconduit extending from said cylinder, and a three-way valve between saidinlet connection, first conduit and second conduit, said valve beingsaid control valve and serving in one of its positions to connect saidinlet and second conduit in order to move said iron to operativeposition, and serving in the other of its positions to connect saidconduit to said first conduit whereby said spring is permitted toexhaust said system and produce the desired air blast.

Referenees (Iitetl in the file of this patent UNITED STATES PATENTS2,160,367 MaXfield May 30, 1939 2,919,990 Podlesak et a1. Jan. 5, 19603,009,298 Gerlach ct a1. a NOV. 21, 1961 3,040,490 Virta June 26, 1962

1. IN A PACKAGING MACHINE HAVING A FILLING PIPE, A TUBE OF PACKAGING MATERIAL DISPOSED AROUND THE PIPE, AND A PAIR OF TRANSVERSELY MOVABLE SEALING JAWS BENEATH THE FILLING PIPE, THE LOWER END OF THE TUBE BEING CLOSED AND DEPENDING FROM THE LOWER END OF THE PIPE TO A POINT BELOW THE SEALING JAWS AND SAID JAWS BEING MOVABLE TOWARD EACH OTHER TO SEAL THE TUBE AT A POINT ABOVE ITS LOWER END, MEANS FOR DRAWING OFF THE SURPLUS AIR FROM THE LOWER END OF THE TUBE COMPRISING A PNEUMATIC SYSTEM FOR CREATING A DISCONTINUOUS AIR BLAST, A CONDUIT CONNECTED TO SAID PNEUMATIC SYSTEM AND EXTENDING INTO SAID FILLING PIPE, THE LOWER END OF SAID CONDUIT BEING SO ORIENTED THAT THE AIR 